1. Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly, to electrical switching apparatus, such as circuit breakers. The disclosed concept also relates to racking assemblies for circuit breakers. The disclosed concept further relates to secondary disconnect assemblies.
2. Background Information
Electrical switching apparatus used in power distribution systems are often mounted within a switchgear enclosure either individually or in combination with other switchgear (e.g., without limitation, circuit switching devices and circuit interrupters such as circuit breakers, contactors, motor starters, motor controllers and other load controllers).
Some electrical switching apparatus such as, for example, some medium-voltage and low-voltage circuit breakers, can be relatively large. In order to facilitate movement (e.g., installation; removal; maintenance), some circuit breakers are commonly coupled to draw-out mechanisms which permit such circuit breakers to be drawn out of the switchgear enclosure. Accordingly, such circuit breakers are commonly known in the art as “draw-out” circuit breakers. The circuit breaker may be further supported within a draw-out frame, commonly known in the art as a cassette or chassis. The switchgear enclosure generally includes a number of compartments or cells, with each cell being structured to receive a corresponding circuit breaker. The draw-out mechanism (also referred to as the racking assembly) includes, for example, a combination of rails and rollers coupled to one or the other, or both, of the sidewalls of the cell and the sides of the corresponding circuit breaker, which is to be drawn into and out of the cell.
Typically, the racking assembly is coupled to the switchgear enclosure making it difficult to accurately indicate the position of the circuit breaker with respect to the switch gear enclosure compartment. That is, it is difficult to mechanically determine if the circuit breaker is, in fact, actually moving (e.g., into the enclosure cell; out of the enclosure cell) with the racking assembly, as opposed to a portion of the racking assembly moving independently with respect to the circuit breaker and/or enclosure. Additionally, it will be appreciated that the secondary disconnects of some medium voltage circuit breakers, for example, must travel a relatively long distance (e.g., up to 10 inches or more) making automatic operation of the secondary disconnects difficult to achieve.
There is, therefore, room for improvement in electrical switching apparatus, such as circuit breakers, and in racking assemblies and secondary disconnect assemblies therefor.